Tac, I think Shawmut Car Shops will do lining - they already paint and line out stuff to order. (I haven't asked but I already posted this on MLS.)
Fred, THIS was done for me by SCS back in 2006, but he used Stan Cedarleaf's decals to to it....
The OP wants to line a British loco, so he's going to need the services of a British decal-line supplier - already mentioned above.
This, OTOH, was done with a ruling pen, and IMO, is perfectly adequate for a working loco like the OP's other examples.
